People using watercraft for travel or recreation often find that storage space for cargo such as camping equipment, clothes, food and other supplies is quite limited. This is particularly true in the case of smaller watercraft, for example a canoe or kayak. One known solution to this problem is to pack articles inside a watertight bag, often referred to as a dry bag, and then tie the bag to the watercraft with a rope or other suitable line. The bag can then be dragged behind the craft within the water while keeping its contents dry. These bags are generally limited to carrying relatively small items, increase the resistance to motion of the craft through the water and tend to develop leaks over time.
U.S. Pat. No. 5,791,280 describes a towable cargo device having a boat-like shape for towing behind a watercraft. The device is connected to the watercraft by means of conventional tow lines. During forward acceleration, these tow lines become taught due to the weight of the device being pulled. However, a loss in forward acceleration may cause the ropes to become slack. This may cause the device to collide with the rear of the watercraft or create a jerking effect thereon when the watercraft accelerates forward and removes the slack from the toe lines. With the lines are slack, the watercraft is only pulling the relatively insignificant mass of the lines forward. Once the lines are stretched taught between the craft and the towable device, the mass of device is added to the load being propelled forward. This sudden increase in mass causes a sudden reduction in the acceleration rate of the watercraft achieved by its driving force, causing the jerk or kickback effect.
U.S. Pat. No. 5,119,752 describes a towable cargo device having a tongue formed by two metal bars for towing behind a watercraft. At a forward end of the tongue, there is provided a hook for attachment to the towing means of the watercraft, which are not detailed in the patent. Where the towing means is a rope or similar flexible connection, it should be appreciated that the aforementioned jerk or kickback may also be experienced when using this particular invention. Alternatively, it may be possible to connect the hook directly to the watercraft to provide a rigid connection which eliminates the jerking effect by maintaining a fixed distance between the watercraft and cargo device. However, this would not allow any relative movement between the watercraft and cargo device, thereby eliminating independent reaction to irregularities in the water surface and therefore reducing ride comfort.
As a result, there is a desire for a cargo carrying device that can be towed behind a watercraft without creating excessive drag or substantially reducing ride quality and corresponding rider comfort.